But remember that the idea of the Nau's ability is that you want to send the Nau out in the unknown, explore new territory, and sell the goods as far from home as possible. That doesn't work very well if you have to send a Worker to build an improvement first.
Oh, I see how it could work nicely like that!
Still would be nice if there was some bonus if the City-State had a Feitoria, to bring the player to set posts in far away lands and further communicate with the City State (it's probably a good idea to be at least friends with the city-states before going to build the feitoria, otherwise every turn your worker spends inside city state territory only hurts your influence with them). Nothing major, +20% money or something, depending on how much money, on average, it brings (the feitoria seems really powerful as it is).
Selling exotic goods doesn't seem to bring any influence with the City-State, which seems a bit clashing: you can trade with them and sell them these goods for ages, yet your relation with them doesn't change one bit from it.
The idea, the way I was seeing it, would be to ally with far way city states and use the feitoria to both gain double resources and allow the city state to earn you money, effectively making it almost like a self-governed colony!
You'd have a bunch of these spread across the map, and routinely send naus to earn money - which, in turn, can be used to invest on more "colonies", or to strengthen the relationship you have with your current ones, or to develop infrastructure in them (you can pay 200
to have resources improved).
I can still do this, though, so I'm still happy!
(And yes, I'm aware I can "colonize" like this already, but as they are, City-States area huuuge money-sink to approach it like that, and no money is earned from it, unlike in the real world where, even if they were only just in the sphere-of-influence, instead of being under direct control, they were still great money-makers for the empire, besides the prestige and status they gave... At least, from my limited understanding of it... Hopefully I'm not saying complete stupidity!
)
TL;DR: My mistake was weighting too much the colonial aspect of Portugal, and glossing over the exploration and trade which are the focus of Portugal for the expansion (and, truth be told, it fits better than the former - unfortunately, though, the only thing in the game helping with overseas colonization is Spain's Conquistador's ability to settle cities. England has a naval movement bonus (and none of the uniques help in this case) and the Netherlands have a diplomatic bonus (and the sea beggar gives a military and gold bonus), both of which can help, but nothing screams for it...)... I dunno, it's late, I think I'm not making any sense whatsoever!
I shouldn't post in this state...